GB2070663A - Multispan greenhouse structures - Google Patents

Abstract

A multiple-span greenhouse structure has side-by-side framed structures each covered with transparent or translucent plastics sheeting. Arched members (12) may be adjusted for height on anchorages (20, 22) by means of lockable rings (30). Ties (36) between adjacent arched members are adjustable for length. The arches may be raised to tauten the plastics sheeting, locked in place and ties secured together. The plastics sheeting may be affixed by battens to inner sides of guttering 44 carried on supports (40) located between arch frame anchorages (20, 22) in common foundations and carrying the ties (36). <IMAGE>

Description

SPECIFICATION Multispan greenhouse structures The invention relates to multiple-span greenhouse structures comprised basically of sideby-side frame structures each covered with transparent or translucent plastics sheeting, usually polythene.

The most satisfactory shape of frame structure has been found to be that of a curved arch, usually comprised of spaced tubular arches tied together by spacers running along the top of the arch. Most often, these arches have been fairly shallow in the sense of being not more than, usually less than, one-half of a circle, and have had a substantially continuous curvature. Previously, we have, ourselves, used such curved arched constructions, and have tied arches of adjacent bays or spans together below channel-section guttering disposed as elevated runs between them with polythene sheeting secured into the guttering using battens.

Generally speaking, such covered garden areas have proved to be most economical when compared with conventional glasshouse structures, and can afford very large covered areas interrupted only by lower parts or legs of the arches.

We have found that the life of polythene sheeting is vastly improved if it can be made very taut, as any slack in it will allow flapping in wind and lead to tearing. Simple telescopic leg provisions allow polythene over singlespan structures to be rendered taut by adjust ment of the arch legs. However, such arrangements are difficult to apply to multispan structures, except at their outer sides, because of the requirement to tie the arches of such adjacent structures together.

It is an object of this invention to provide a simple solution to the latter problem.

To this end, we now propose that arch frame elements of adjacent spans each be length-adjustable relative to upstanding anchorages therefor and have couplings for elongate ties between adjacent arch elements, which couplings afford at least one of, preferably bolts, freedom of movement of the coupling along the arch elements and variation of tie length between engagement by the couplings.

Particularly simple and reliable couplings that further àcilitate ease of assembly of multispan structures comprise rings or collars slidable over tubular arch elements and selectively lockable thereon, preferably having locking bolts in radial threaded through-bores, which bolts further preferably extend through axially extending slots in end parts of the ties which are captive thereon by reason of the bolt heads. Packings or spring washers are readily provided on such bolts to permit final locking up and securement of the overall Similar rings or collars with locking bolts are readily used for setting extension of the arch elements relative to tubular or post-like said anchorages with which they are telescopic, preferably overfitting so that the setting rings or collars are on the smaller section anchorages to act as seats for ends of the arch elements.

Clearly, at least using our preferred ring or collar type tie-to-arch couplings, the ties may well be at different heights. Thus, we prefer to mount guttering channels on their own upstanding post or tube supports normally set between the arch element anchorages. Such guttering supports then permit desired gutter slopes to be set wholly independently of the arches, say by mounting the latter on crosspieces secured to the upper ends of those supports.

Furthermore, the use of such gutter supports permits the most advantageous location thereon, at adjustable heights, of the ties at a medial position of the latter, preferably also via a ring or collar of the same general type as mentioned above.

The ties and various couplings hereof lead to great ease of erection where the arch element anchorages and the gutter supports are set in concrete foundations, usually with the ties then captive on the gutter supports; the guttering is fitted to the gutter supports and the arch elements are fitted over their anchorages at substantially less than maximum heights available; the ties and arch couplings are connected together loosely; the arches of the bays are covered with suitable plastics sheeting, usually of polythene, with edges thereof wrapped over battens bolted or screwed, preferably the former, into inner sides of the guttering; the arches are pushed up to render the sheeting taut and secured at those heights; and the tie couplings are tightened up to secure the integrity of the overall multispan structure.

Clearly, at any time after erection any stretching of the plastics sheeting can be taken up by further adjustment of the arches and ties.

One other matter has arisen in devising the preferred embodiments of this invention, namely improvements of the shape of the arches so that lower or side parts thereof are substantially straight and vertical, or nearvertical, and that curving of the arches begins at or just below the position for the ties, i.e.

just below the guttering, and with pronounced portions of greatest curvature thereat, which substantially reduces the extent over and to which the plastics sheeting is free of direct support by the arches in being taken into the guttering for batten-securement thereto.

One particularly advantageous implementation of the invention will now be described with reference to the accompanying diagram matic drawings, in which: Figure 1 is an end view of adjacent arches, spans or bays of a multispan structure; Figure 2 shows two adjacent arch support parts; and Figures 3 to 7 show details.

In the drawings, a multiple span structure has adjacent spans such as 1 OA, 1 OB, 1 0C, etc. extending through the plane of Fig. 1.

Each span comprises a plurality of arch elements 1 2 spaced at intervals along its length and tied together at 1 4 along their highest position.

The arch elements 1 2 are tubular and have substantially straight, vertical or near-vertical sides or legs 16, 1 8 that overfit upstanding posts or tubular anchorages 20, 22 secured down firmly, often concreted 24 directly into foundation holes in the ground 26 as shown.

The upstanding anchorages 20, 22 extend to a desired or prescribed extent into the sides or legs 16, 1 8 of the arch elements 1 2 and carry collars or rings 30 capable of sliding thereon except when clamp bolts 32 thereof are tightened to set those collars or rings to a desired position whereat they act as seatings for the ends of the arch sides or legs 16, 1 8.

Tie bars 36 are shown extending between adjacent arch legs or sides 16, 1 8 of intermediate junctions between the spans or bays 10 and these (see Figs. 2, 4 and 5) are carried by a ring or collar bracket 38 secured, for example welded, thereto and slidable on a tubular post 40 except when clamped thereto by bolts 42. The tubular posts 40 serve as supports for channel section gutters 44 running the length of the overall structure at each intermediate junction between adjacent spans or bays 10 thereof.

The tie bars 36 are also coupled to the arch elements 1 2 by way of rings or collars 50, 52 capable of sliding on the arch elements and having clamp screws or bolts 54 that extend through longitudinal slots 56, 58 in end portions of the tie bars. The clamp bolts 54 render the tie bars 36 captive on the ring or collar couplings 50, 52 and, until tightened up, will allow freedom of movement of the latter on the arch element 1 2 and along the tie bars 36.

Plastics sheeting 60, usually polythene, is laid over the arch elements 1 2 of each span or bay 10 and secured to the gutter 44 by way of battens 62 about which ends of the sheets are wrapped and the battens 62 bolted (64) into the divergent sides of the gutter 44.

The battens of the gutters 44 are shown bolted onto cross-pieces 58 on the tops of the support posts 40 (see Fig. 3).

Fig. 1 also shows end framework in the form of spaced uprights 70 and upper crosspieces 72 for each bay or span to allow any desired in-filling, cladding or sheeting-over.

The first stage in the erection of a multispan structure hereof will be setting into the ground, conveniently using concrete foundations 24, the arch element anchorages 20, 22 and the gutter supports 40, and, where desired, at 74, the uprights 70 of the end frameworks 70, 72.

The gutter supports will carry the tie bars 36 and their ring or collar couplings 38 captive thereon and the guttering 44 is conveniently installed on the cross-pieces 58 as the next step. Obviously, if the posts are not of exactly the right height or the desired gutter slope, suitable packings can be fixed between the guttering and the cross-pieces 58.

The rings or collars 30 will then be set on the arch anchorage posts 20, 22 at a low height, or left free to rest on the foundations 24, and the arch elements 1 2 slipped onto the anchorage posts 20, 22 telescope-fashion.

Those arch elements 1 2 preferably already carry the coupling rings or collars 50, 52 which may be temporarily clamped thereto.

Then, the bolts 54 thereof will be passed into the rings or collars 50, 52 through the slots 56, 58 in the tie bars 36 with the latter raised on and, if desired, clamped to the gutter supports 40 with the bolts 54 at or near outermost ends of the slots 56, 58.

The sheeting 60 is then laid on, and fixed in the guttering 44, for tensioning by raising the arch elements 1 2 on their anchorage posts and securing them at the desired height using the rings or collars 30. During such raising of the arch elements 12, they are free to pass through the ring or collar couplings 50, 52 and the latter are free to move along the tie bars 36. After tensioning of the sheeting 60 and setting of the arch elements 1 2 on the rings or collars 30, the bolts 54 of the couplings 50, 52 can be tightened up, if necessary or desired using packings and/or spring washers to ensure gripping of the tie bars 36 and clamping engagement of the bolts 54 on the arch elements 1 2.

It will be noted from Fig. 7 that the arch anchorage posts 20, 22 and the gutter support 40 at each foundation therefor have a triangular disposition, which enables the former to be as close together as desired and the latter to be offset as required to accomodate to the tie bar couplings.

The drawings, particularly Fig. 1, accentuate the straightness of the arch side portions 16, 1 8 and the curvature upwardly therefrom to the arch span proper. However, the basic idea of the arrangement is particularly successful in ensuring that, after lifting the arches to tension the plastics sheeting, the latter has a minimum spacing from the arches into the gutters. Thus, it is preferred that the gutter heights be set to accomplish this.

In a typical particular arrangement, using gutter heights of about or just over 2 metres to give adequate head room throughout the multispan structure, the spans will be about 6 metres wide and about 3 > metres maximum height. Suitable end-frameworks would then be about 2.35 clearance height, and the arches disposed at 2 metre intervals. Then, a suitable capability for adjustment of the arch elements on the anchorages has been found to be about 3-4 cms, though the extent of overlap will obviously be much more.

Claims (20)

1. A multiple-span greenhouse structure having side-by-side framed structures each covered with transparent or translucent plastics sheeting, wherein each of the framed structures comprises spaced substantially parallel arch-frame-elements each length-adjustable relative to upstanding anchorages therefor and with substantial registration of such archframe-elements of adjacent framed structures, the thus adjacent arch-frame-elements being interconnected by elongate ties extending between couplings to those adjacent arch-frameelements, such ties and couplings having freedom of movement to vary tie length between engagement by the couplings and/or couplings along their associated arch-frame-elements.

2. A multiple-span greenhouse structure according to claim 1, with the arch-frameelements adjusted relative to their anchorages and tied to adjacent arch-frame-elements of the next framed structure with the plastics sheeting taut over the arch-frame-elements of each framed structure.

3. A multiple span greenhouse structure according to claim 1 or claim 2, wherein each said coupling comprises a ring or collar slidable' over said arch-frame-elements and selectively lockable thereon.

4. A multiple-span greenhouse structure according to claim 3, wherein each said coupling is so lockable by bolts in radial threaded througholes.

5. A multiple-span greenhouse structure according to claim 4, wherein the said ties are axiaily slotted in end parts thereof held captive and lockable by said bolts.

6. A multiple-span greenhouse structure according to claim 5, further having packings and/or spring washers to aid locking of the ties or this couplings.

7. A multiple-span greenhouse structure according to any preceding claim, wherein said arch-frarne-elements are tubular and fit teiescopically over smaller section tubular posts as said anchorages.

8. A muitiple-span greenhouse structure according to claim 7, wherein adjustment of said arch-fran1e-eíerrlents relative to said posts is by way of rings or collars slideable over and lockable on said posts te act as seats for ends of the arch4rame-elements.

9. A multiple-span greenhouse structure according to any preceding claim, wherein upstanding gutter supports are located at positions between those of the anchorages of adjacent ones of said arch-frame-elements of side-by-side said framed structure.

10. A multiple-span greenhouse structure according to claim 9, wherein the positions of the gutter supports and the upstanding anchorages are in triangular groups sharing the same foundation.

11. A multiple-span greenhouse structure according to claim 9 or claim 1 0, wherein the gutter supports determine slope of guttering channels carried on tops of the gutter supports.

1 2. A multiple-span greenhouse structure according to claim 11, wherein the tops of the gutter supports have cross-pieces carrying said guttering channels.

1 3. A multiple-span greenhouse structure according to any one of claims 9 to 12, wherein said ties are medially located in a height-adjustable manner on said gutter supports.

1 4. A multiple-span greenhouse structure according to claim 13, wherein the medial location is by rings or collars fixed to the ties and both slidable and lockable on the gutter supports.

1 5. A multiple-span greenhouse structure according to any one of claims 9 to 14, wherein said plastics sheeting is secured over each framed structure via battens secured to guttering, or said guttering channels, supported by said gutter supports.

1 6. A method of erecting a multiple-span greenhouse structure according to claim 15, wherein said anchorages and gutter supports are set in concrete foundations, guttering is fixed to the gutter supports on which ties are then captive; said arch-frame-elements are fitted over their anchorages at substantially less than maximum available height; the ties and associated arch couplings are connected together loosely; the arches of each framed structure are covered with plastic sheeting with edges thereof wrapped over battens secured to inner sides of the guttering; the arches are pushed up to render the plastics sheeting taut, and secured at the corresponding heights; and the ties and their couplings are tightened up to secure the integrity of the overall multispan structure.

1 7. A multiple-span greenhouse structure according to any one of claims 1 to 15, wherein the ties and their couplings are at or adjacent to portions of the arch-frame-elements of greatest curvature from substantially straight and vertical or near vertical at and above said anchorages to a relatively shallow crown portion.

18. A multiple-span greenhouse structure according to claim 1 7 with claim 15, wherein said guttering channel is just above said ties and close to said greatest curvature portions of the arch-frame-elements to reduce the extent over and to which the plastics sheeting is free of direct support by the arch-frame-ele ments in passing into the guttering for securement purposes.

1 9. A multiple-span greenhouse structure substantially as herein described with reference to and as shown in the accompanying drawings.

20. A method of erecting a multiple-span greenhouse structure according to claim 1 substantially as herein described.